1. Field of the Invention
This invention relates to insulated steel structural panels and, more particularly, to a method and apparatus for providing a natural-looking stucco appearance to those panels when they are manufactured.
2. Description of Related Art
The recent development of structural steel panels that incorporate highly effective insulation has been a boon to construction of commercial and industrial buildings. These panels are generally formed of a central core of expanded foam material that is sandwiched between two layers of steel sheathing in a product that may be manufactured economically in efficient production facilities and transported to a construction site. These panels may be used for exterior walls or roof panels of a building, or may be used to construct cold storage facilities inside existing warehouses. Insulated structural steel panels offer the advantages of quick and easy construction by bolt-on assembly to a steel framework, very high insulating values, sealed edge conformations that prevent air infiltration, and a high strength/weight ratio.
Typically, the steel layers that form the outer surfaces of the panels are painted or coated for esthetic purposes, as well as to protect the steel material from corrosion (although the steel is often galvanized for anti-corrosion purposes as well). It is also a common practice to emboss at least the outer steel sheet with a pattern that softens the visual appearance of the panel and reduces the industrial or “machine-made” impression of the panel. The embossing step typically takes place before the painting or coating process so that the paint or coating is not abraded or removed by the embossing rollers.
Despite the provision of embossment on the outer panel surfaces, many building designers choose to add a surface treatment to the insulated panels to produce a more earthy, recognizable and appealing appearance. Thus, a building constructed of insulated steel panels may be treated with a stucco exterior coating which softens the appearance of the steel outer skin. This coating, which may be sprayed onto the exterior surface of the building, adds a significant cost to the construction, and may be problematic in other ways. The stucco coating requires a period of warm and dry weather to enable the application and curing of the stucco, and some climates do not experience such weather very often. For example, insulated structural steel panels are frequently used in cold northern climes, where snow, rain, and sub-optimal temperatures may delay the application of an exterior stucco coating for many weeks. Thus the conclusion of a building project may be held up unduly, and building occupation and construction contract completion postponed.